Not too long ago I decided to do a well deserve maintenance and tackle the issues I’m having with my 26-channel Matchless. I had it been completely recapped a few years back and all the channels were fitted with Langley Upgrades, which btw are absolutely awesome. I barely use anything else since I have these.

We have just entirely recapped the AMEK 2000 Serie PSU that came with it. Big improvement!

However, the issues are:

1a- After recapping all the meters if found that the one for channel 1 is behaving rather erratically and the 8th green led from the bottom end is constantly on. I went on and replaced the LM319 comparator associated with it, along with the associated 2.2k resistors and the 2N3906 transistor, to no avail.1b- The Master left meter goes off quite often.

BTW, believe it or not, a lot of these caps were completely out of specs. But the worst were the 2,2µF that read close to zero!!!

2- The DIM switch never worked on this console since I bought it. When it’s depressed, the COMM indicator goes on and the sound is muted.I’ve checked the schematics, and everything “appears” to be alright....

3- The Talkback works fine except that the external mic has to be a dynamic mic, because despite what the manual says, a condenser mic does not work at all. The internal mic, that was apparently hard wired to the board, had been disconnected by the previous owner. A Molex connector was fitted. BTW, the gain is quite low on this thing. I have to crank it up all the way to hear something.

Obviously The DIM switch issue and the mic (phantom power)/talkback issue are interconnected. But I can’t pinpoint the issue.

4- While doing that maintenance I was going through the manual I have, and it says that the MCDS2000 have ribbon cables connected to them. Mine don’t have any, and there is not a single empty Molex or other type of connector whatsoever on any of them.

5- I also have what behaves like a MONO switch right below the VU/PEAK button on the Master Channel (MCDS4000). This button doesn’t appear anywhere on the manual.Also the Light Meter Master Card fitted on my console doesn’t exactly reflect the schematic I have.Some polarities are backwards.

6- When calibrating the meters, I need 1.228v for +4dB and then trim pot to 0. It probably sounds dumb to most of you, but is this AC do DC? And where precisely on a Matchless do I have to take thes readings?

Any help in identifying the console and/or troubleshooting these issues would be greatly appreciated.

Your desk seems to be either a pre-production version or is modified. That makes it difficult to answer your questions. Most things should be addressed by measuring at location, not from remote.1,224V/+4dB is AC

jensenmann wrote:Your desk seems to be either a pre-production version or is modified. That makes it difficult to answer your questions. Most things should be addressed by measuring at location, not from remote.1,224V/+4dB is AC

From what I can tell my desk has not been modified. That “Mono” switch for example, seems to be stock. The hole in which it’s located has not been cut or drill after the paint was applied.However it’s definitely a very early run.

the BUS GROUP channel must have molex connected. does your console have a patchbay? maybe it was the big frame and the group channels are on the wrong position and you can not find the ribbons because they are hidden beneath ather channels. do you got schematics? then everything falls in place. i miss the mono switch, you got one build in. its not original and on a not very comfortable posiotion. i would replace the DIM with the Mono. dim is not as usefull then MONO... my point of view....

themixfarm wrote:the BUS GROUP channel must have molex connected. does your console have a patchbay? maybe it was the big frame and the group channels are on the wrong position and you can not find the ribbons because they are hidden beneath ather channels. do you got schematics? then everything falls in place. i miss the mono switch, you got one build in. its not original and on a not very comfortable posiotion. i would replace the DIM with the Mono. dim is not as usefull then MONO... my point of view....

No patchbay. All the AUX channel strips are in the correct position. Yes, I do have all the schematics.Yes, the Mono switch on my console is completely original. It was not added by someone else.But I do agree that the placement is awkward.

studiotim24 wrote:Hi , Can anyone tell me what the current output is on the AMEK 2000 psu +/-17v rails

AMPS /RAIL please ?

best Regards Tim

I don’t have the exact figures off the top of my head, but after completely servicing and recapping it, it’s about 18v at 8A if I recall correctly. I replaced a couple of voltage regulators, all the electrolytic caps, a couple of resistors and some diodes.